buildpack-deps?In spirit, buildpack-deps is similar to Heroku's stack
images. It
includes a large number of "development header" packages needed by various
things like Ruby Gems, PyPI modules, etc. For example, buildpack-deps would
let you do a bundle install in an arbitrary application directory without
knowing beforehand that ssl.h is required to build a dependent module.
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This stack is designed to be the foundation of a language-stack image.
The main tags of this image are the full batteries-included approach. With
them, a majority of arbitrary gem install / npm install / pip install
should be successfull without additional header/development packages.
For some language stacks, that doesn't make sense, particularly if linking to arbitrary external C libraries is much less common (as in Go and Java, for example), which is where these other smaller variants can come in handy.
curlThis variant includes just the curl, wget, and ca-certificates packages.
This is perfect for cases like the Java JRE, where downloading JARs is very
common and necessary, but checking out code isn't.
scmThis variant is based on curl, but also adds various source control management
tools. As of this writing, the current list of included tools is bzr, git,
hg, and svn. Intentionally missing is cvs due to the dwindling relevance
it has (sorry CVS). This image is perfect for cases like the Java JDK, where
downloading JARs is very common (hence the curl base still), but checking out
code also becomes more common as well (compared to the JRE).